STRIKE UP THE BAND! Around the world today, February 12, admirers of Charles Darwin will celebrate the great man's 198th birthday with lectures, concerts, and exhibits.

Darwin Day, as it's called, is meant to be cheerful, with a bit of good-natured triumphalism, marking what celebrants see as the intellectual victory of Darwinism, the theory of evolution by the purely material mechanism of natural selection. But set aside the scientific legacy for a moment to consider the less frequently discussed question of Darwin's moral heritage. This year happens to mark another anniversary as well: a tragic one, strongly linked to Darwinian theory.

As of 2007, it is exactly a century since the key turning point in the Darwin-inspired American eugenic movement. In 1907, the state of Indiana achieved the distinction of becoming the world's first government entity to enforce sterilization of institutionalized "idiots," "imbeciles," and other individuals deemed genetically "unfit." The idea caught on.

With Washington and California following in 1909, some 30 states eventually passed similar compulsory sterilization laws by the early 1930s. California was the leader in the field, accounting for half of the coercive sterilizations in the years leading up to World War II.

By 1958 some 60,000 American citizens had been sterilized against their will. Only the horrors of Nazism succeeded in casting a pall over America's romance with eugenics, when it became widely known that German doctors were following the lead of their California colleagues and sterilizing undesirables.

"EUGENICS" is a word coined by Darwin's cousin, Francis Galton in

That eugenics traced its origins to Darwin was no secret. A leading scientific eugenicist, the Harvard genetic biologist Edward East, explained in 1927 that "eugenic tenets are strict corollaries" of the "theory of organic evolution."

It was a reasonable inference. In his Origin of Species in 1859, Darwin described the "one general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die."

His more specific thoughts on human society were saved for his other major work, the Descent of Man (1871):

With savages, the weak in body or mind are soon eliminated; and those that survive commonly exhibit a vigorous state of health. We civilized men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed, the sick; we institute poor-laws; and our medical men exert their utmost skill to save the life of every one to the last moment . . .

Thus the weak members of civilized societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man.

Darwin himself opposed discriminating against the weak and helpless, but his disciples were less principled. The major ethical impact of the Darwinian idea has been to undercut what contemporary Princeton bio-ethicist Peter Singer decries as the "Hebrew view" of a purposefully-designed humanity, crowned by the solemn and central theme: "And God said, Let us make man in our image."